Washing/drying machines typically comprise four configurations: 1) vertical-axis; 2) horizontal-axis; 3) vertical-axis rotatable to a horizontal or inclined axis and 4) inner and outer washing and drying tubs wherein the washing tub remains vertical while the drying tub remains horizontal.
U.S. Pat. No. 3,376,718 to Kahn, issued Apr. 9, 1968, discloses the first type of washing/drying laundry machine which comprises a vertical water container, a perforated dehydrating tub supported in the water container for rotating about a vertical axis, and an agitator rotatably supported in the dehydrating tub. To wash and rinse the laundry, the laundry is loaded in the water container, water is supplied to the water container, and the agitator is rotated. Subsequently, water is drained from the water container, and the dehydrating tub is rotated at high speed to dehydrate the laundry. In this configuration, the tub remains in a vertical orientation through the washing and dehydrating process. Air for drying is injected into the tub from above and is exhausted at the base.
U.S. Pat. No. 5,029,458 to Obata et al., issued Jul. 9, 1991, discloses the second type of washing/drying laundry machine which comprises a horizontal water container and a horizontal perforated rotation tub. The rotation tub is supported in the water container so that the tub can rotate about a horizontal axis. After the laundry is loaded in the rotation tub and water is supplied to the water container, the rotation tub is rotated to wash and rinse the laundry. Subsequently, water is drained and the rotation tub rotates at high speed to dehydrate the laundry. In this configuration, the tub remains in a horizontal orientation throughout both the washing and drying process.
U.S. Pat. No. 5,074,131 to Hirose et al., issued Dec. 24, 1991, discloses the third type of washing/drying laundry machine which comprises a vertical water container and a vertical perforated rotation tub. The rotation tub is supported in the water container so that the tub can rotate about a vertical axis. After the laundry is loaded in the rotation tub and water is supplied to the water container, the rotation tub is positioned with an inclined orientation where it is rotated to wash and rinse the laundry. Subsequently, water is drained and the rotation tub rotates at high speed to dehydrate the laundry. In this configuration, the tub is in a vertical position during the washing cycle and in an inclined position during the drying cycle when air is injected into the tub from its opening end, which is located slightly above horizontal.
U.S. Pat. No. 5,058,401 to Nakamura et al. issued Oct. 22, 1991 discloses the fourth type of washing/drying laundry machine which comprises a water tub, a ring supported in the water container for rotating about a vertical axis, a perforated spherical container supported in the ring for rotating about a horizontal axis, a drive means for rotating the spherical container and the ring, and a change means for controlling the drive means and for choosing between the horizontal and the vertical rotations of the spherical container and the ring. After the laundry is loaded in the spherical container and water is supplied to the water tub, only the container rotates about the horizontal axis to wash the laundry. Subsequently, in order to dehydrate the laundry, the water is drained and the ring and the container rotate about the vertical axis at high speed. Warm air for drying is introduced along a horizontal axis of the spherical container. In this configuration, the tubs remain in their original orientations, vertical during the washing cycle and horizontal during the drying cycle.
The present invention relates to the first type of washing/drying machine which remains vertical. The primary design flaw of this type of machine is its inability to properly agitate the clothes in the vertical tub during the drying cycle. After the laundry is washed, the laundry is generally entangled and accumulates in the bottom of the rotation tub. Since the tub in a vertical orientation, drying the clothes evenly is difficult. Even when the tub is rotated, as in a dehydrating cycle, the clothes tend to stick to the side.
A solution to the vertical tub drying operation would be to utilize a horizontal tub for washing and drying, i.e., the second type of machine. This second type of washing/drying machine requires less water and has less entangled laundry than the first laundry machine. However, during rotation, the horizontal-axis tub loses its balance and vibrates due to the unbalanced load of the laundry, thus generating noise. Corrective weights, for preventing the noise, make the laundry machine heavier and manufacturing costs higher. However, horizontal tubs are notorious for leaking. Similarly, if the latch of a horizontal tub washing/drying machine fails or is accidentally disengaged, the entire contents of the tub will empty into the room.
A solution to the all vertical and all horizontal operations would be to utilize a vertical mechanism rotatable wash tub that can be moved to an inclined or horizontal position for drying, i.e., types 3 or 4. However, this movement requires complex parts, adding significant costs and potential for failure.